Steam-pressure indicator.



Patented Dec. 9, l|902.

E. A. HrrcHcuCK.

STEAM PRESSURE INDICATOR.

'Application led May 26, 1902.)

(No Model.)

A TTOHNEY UNITED STATES PATENT OFFICE.

EMBURY A. HITCHCOCK, OF COLUMBUS, OHIO.

STEAM-PRESSURE INDICATOR.

SPECIFICATION forming' part of Letters Eaten?. No. 715,382, datedDecember 9, 1902.

Application filed May 26| 1902. Serial No. 108,954. (No model.)

T0 all whom, it 11b/,ty concern:

Beit known that I, EMBURY A. HITCHCOCK, a citizen of the United States,residing at Columbus, in the county of Franklin and State of Ohio, haveinvented a certain new and useful Improvement in Steam-PressureIndicators, of which the following is a specification.

My invention relates to steam-engineindicators of that class which areadapted to produce a penciled design on an indicator-card indicatingsteam-pressure; and the objects of my invention are to provide anindicating device of this class with improvements whereby the samepencil-lever-operating mechanism may be employed for producingindications I'rom both low and high pressure cylinders and to producewhen either of said pressures are being indicated substantially thesame-sized diagram and to produce certain improvements in details ofconstruction, which will be more fully pointed out hereinafter. Theseobjects I accomplish in the manner illustrated in the accompanyingdrawings, in which- Figure l is a central vertical section of anindicator,showing my improvementin connection therewith and showing thecard-carrying drum in elevation; and Fig. 2 is an outer side View of thelower portion of the indicatorbody.

Similar numerals refer to similar parts throughout the several views.

In carrying out my invention I employ a suitable casing or cylinder, thebody of which may consist in the usual or well-known form of upper andlower united cylindrical sections l and 2, said lower section havingleading downward therefrom a terminal casing-section 3, which in thepresent case is enlarged in its lower portion to form a terminal chamber4, the upper section of which is preferably constructed with anexternal. sleeve 5 and is provided with an upper end cap 6, loeneathwhich,within the upper section l,is provided a spring bearing-head 7.

8 represents a vertical piston-rod which eX- tends centrally through thecap 6 and which being formed tubular is internally threaded to receivethe threaded portion of an upward extension 9 of said piston-rod. On thelower end portion of said piston-rod and within the cylinder is carrieda piston I0, which is adapted to rit and slide within said cylinder.

ll represents the usual spring, which is arranged between thebearing-head 7 and the piston l0.

The upper end of the piston-rod extension 9 has pivoted thereto in itsouter end portion a laterally-extending pencil-carrying lever 12, theadjacent end of which is pivotally connected with a standard 13, risingfrom the indicator casing or body. The piston-rod eX- tension 9 is alsopivotally connected with one end of a guide-link I4, the remaining endof which is connected with a bracket-arm l5, rising from the sleeve 5.

The outer end of the lever l2 is adapted to carry in the usual manner ata point 16 a pencil the point of which is adapted in the mannerhereinafter described to be moved over the surface of a paper held byspringstrips 17 on a vertical oscillating drum 18, which receives itsmovement in the usual manner from the reducing mechanism of the enginethrough a cord 19.

In carrying out my improvements I provide the piston l0 with a centraldownwardly-extendingrod 20, which carries on its lower end a secondpiston 21, the latter being of less circumference and area than thepiston 10 and fitting and adapted to slide within an open-end cylinder22, which is arranged centrally within the casing terminal chamber 4.Connecting the space below the open-end cylinder 22 with a space abovethe same and loeneath the piston 10 are side steam-passages 23, andwithin each of the latter is rotatably mounted a valve 24. Each of thesevalves 24 has formed therethrough, at right angles with the direction ofits length,an opening 25, and leading from this opening 25 through oneside of each of said valves is a port 26, this latter port being adaptedto register, when the valve is in a closed position, with a port 4through the wall of the chamber. As indicated in Fig. 2 of the drawings,the corresponding outer ends of the valves 24 on the outer side of theenlargement 4 are provided with meshing gear-segments 27, one of thelatter having connected therewith an operating-lever 28.

With the lower end outlet-coupling extenroo sion 29 is adapted to beconnected a steaminlet pipe which may be provided with the usuallve-way-valve mechanism, thus providing for the connection of four pipestherewith, one from each end of a low-pressure cylinder and one fromeach end of a highpressure cylinder. This construction, however, is wellknown and is not herein shown.

In order to illustrate the operation of my device,we will assume thatthe lower end portion of the chamber 4 is properly connected with theends of a high-pressure cylinder and that the valves 24 are in theclosed positions indicated in Fig. l. The parts being in this positionit is obvious that the steam-pressure will be against the comparativelysmall piston 2l and that the operation of raising the piston 10 withinits cylinder and against the spring 1l will result in the usualoperation of the pencil-carrying lever l2 and in the production of apressure-diagram upon the card carried in the usual manner by theoscillating cylinder 18. Assuming, however, that the connection with thelower` end of the terminal chamber 4 has been made with the ends of thelow-pressure cylinder,the valves 24 are turned so that the upper andlower portions of the passages 23 communicate through the centralopenings of the valves, with the result that the under side of thepiston lO,which is of greater area than the piston 2l, is subjected tothe pressure of steam from the lowpressnre cylinder. By thus subjectingthe larger piston lO to the pressure of steam from the low-pressurecylinder a 'sufficient movement of said piston IO and rod 8 is impartedto produce a movement of the pencil-holding lever which will result inthe production of substantially as large a diagram upon the card as thatproduced by the pressure of the steam from the high-pressure cylinderagainst the piston 2l. When the valves 24 are in the closed position, itis obvious that any steam which may have accumulated between said valvesand the under side of the piston lO will be permitted to exhaust throughthe valveopenings 26 and 25 and the casing-openings 4a. I also providein the usual manner in the upper portion of the cylinder l a steamoutletport 4b to permit the escape of steam which may accumulate in saidcylinder above the piston 10.

It is well known that in obtaining accurate results in determininghorse-power through steam-engine indicators it is desirable that thediagram be drawn as large as possible, and in compound engines, wheresteam is gram from the low-pressure cylinder as from the high-pressurecylinder and that this is accomplished by the employment of oneindicator and but one spring. It will be understood that inaccomplishing the objects of my invention the upper and lower pistonsbear approximately or exactly the same relation to each other withreference to area as the two pistons of the engine.

In using myimproved indicator in conjunction with a compoundsingle-acting engine, where the cylinders are in close proximity to eachother, the connection with the indicator could be made with the twocylinders and accomplish thereby the same result as two indicators. Itis also obvious that in the employment of long-stroke multiple-extensionengines,where the cylinders are in close proximity to each other, myimproved indicator would be of great advantage and is particularlyadapted for use in connection with compound locomotives. It will also beobserved that the construction of the improved parts of the indicatorherein shown and described is without undesirable complication and thatthe same may be produced at a comparatively low cost.

Having now fully described my invention, what I claim, and desire tosecure by Letters Patent, is-

In a steam-pressure indicator, the combination with a cylinder having aterminal extension 4, the latter having an inlet in its lower portion,and an open-end cylinder within said extension and valve-controlledpassages 23 connecting the spaces above and below the inner cylinder, ofa piston in said upper cylinder, a piston in said lower internalcylinder connected with said upper piston, a rod rising from the upperpiston, a pencil-carrying lever connected with said rod and a springinterposed between the upper portion of the cylinder and the upperpiston, substantially as specified.

EMBURY A. HITCHCOCK.

In presence of- O. C. SHEPHERD, A. L. PHELPS.

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